Figure 6.

(A) Hemagglutinin inhibition assay for quercetin. 4HAU influenza A/Puerto Rico/8/34 (H1N1) virus was incubated with serally diluted quercetin at room temperature for 30 min. 0.5% cRBCs was added, and the virus then incubated at room temperature for 1 h. Note the inhibition on hemagglutination of quercetin; (B) Hemolysis inhibition assay of quercetin against the influenza A/Puerto Rico/8/34 (H1N1) virus strain. Quercetin diluted in PBS was mixed with an equal volume of the influenza virus A/Puerto Rico/8/34 (H1N1) in a 96-deep well plate. After incubating at room temperature for 30 min, 2% chicken erythrocytes pre-warmed at 37 °C were added. The mixture was incubated at 37 °C for another 30 min. To trigger hemolysis, sodium acetate (0.5 M; pH 5.0) was added and incubated at 37 °C for 15 min. Plate was centrifuged at the end of incubation at 3000 rpm for 5 min, and the supernatants were transferred to another flat-bottom 96-well plate. The OD₅₄₀ was read on a microtiter plate reader.